A Global Understanding Of The Factors Facilitating Plant Invasions.
Globalization has resulted in the anthropogenic movement of plant species, many of which have established and become invasive in their secondary ranges. A fundamental goal in invasion ecology is to understand the factors that contribute to successful establishment and spread of invasive species on a global scale. Given the likelihood of a future with increased international connections leading to introductions of plant species, understanding why some species are successful invaders and which ecosystems are susceptible to invasion continues to be crucial to development of effective preventative policy and management strategies. Although there is a large body of literature on determinants of invasion success, substantial gaps remain in how the effects of evolutionary history, global connectivity, and habitat suitability of native and introduced regions affect the propensity for a species to become invasive and the propensity for a region to be invaded. This dissertation research addresses these uncertainties with three independent but complementary studies using global databases: 1) evaluating the relative likelihood of successful plant invasions by comparing phylogenetic diversity, habitat suitability, and anthropogenic connectivity between native and non-native regions; 2) incorporating the effect of spatial scale on outcomes of those processes; and 3) determining contributing factors of regional invasibility and predicting potential future invasions. A global approach to invasion science is powerful in building a general understanding of factors that influence establishment and spread. Cumulatively, results showed that characteristics of invasive species’ native ranges were more important than characteristics of the invaded range when modeling invasiveness, namely phylogenetic diversity. In addition, this work highlighted the effects scale on factors of invasion success. Finally, we developed a novel method to quantify invasibility of regions and predict which regions have high potential for future invasions. Conclusions from this work suggest that development of effective preventative policy and management strategies should include diversity of invasive species’ native range. Furthermore, prevention of invasive species requires careful consideration of the future potential of invasibility. A global approach to invasion science is powerful in building a general understanding of factors that influence establishment and spread. The outcomes of this work have numerous implications for understanding global dynamics of how and why species invade.